CMS not allowing WebEx Desktop minis to unmute

[Jim Harlow]

We have just received our Cisco Webex Desktop Minis  and have begun installing 200 of them.  Some of our users are having an issue unmuting when joining bridged calls that they unmute  but cannot be heard.  We looked on CMM and it showing muted even though we are unmuted on the device.  Has anyone heard of or had this issue.  We are a secured environment so we are not at the latest firmware levels.  Just trying to find out we are the only ones.

[b.winter]

Where are the Webex devices registered? To CUCM?
If yes, which SIP profile have you configured in the device config page of the Webex devices?
Are the devices using a SIP profile, where the parameter "Allow iX Application Media" is checked? If no, you should assign them the standard SIP profile "Standard SIP Profile For TelePresence Endpoint" or a copy of it.

[Jim Harlow]

First I want to say thanks for helping.  That is how we have our systems set up, registered to CUCM with the standard SIP profile.  What we found is the back-up we were using is setting the MTU to 1280.  By changing that to 1350 it stopped the issue from happening.  Our network folks have to make a change to allow us to use 1500.

[b.winter]

If it works now, OK.
But which "back-up" do you mean? And where did you change the MTU size?

[Jim Harlow]

By "back up" I mean one our engineer configured and we backed up and used as a master when installing others.  MTU size is in the Network tab.